Komatsu SA6D155-4A(S/N 50816-UP)
Maintenance schedule, common problems & OEM parts breakdown
The Komatsu SA6D155-4A is a turbocharged, six-cylinder diesel engine rated at 410 hp (measured at 2,000 rpm) with a displacement of 1,175.4 cu in (19.2 L). It powers the Komatsu D355A series crawler tractors, specifically the D355A-1 and D355A-3 models, which are heavy-duty dozers with operating weights ranging from 97,907 lb to 105,557 lb (44,400 kg to 47,900 kg). Production years for the D355A series span the late 1990s through the 2000s. The SA6D155-4A succeeded earlier S6D155-4 variants and was later replaced by the SA6D155-4A-35 (S/N 20338-UP) to meet stricter emissions standards. Configurations offered include high-altitude specs and specific starting engine variations.
Across the D355A series generations, the primary change was the transition from the SA6D155-4A to the SA6D155-4A-35, driven by the need for Tier 2 to Tier 4 emissions compliance. The SA6D155-4A remains significant in the used and parts market because it is a robust, mechanically simple powertrain found in heavy earthmoving equipment that is now aging out of warranty. Its widespread use in the D355A line ensures a steady supply of aftermarket support, while its specific serial break at S/N 50816-UP distinguishes it from earlier hanging-type engine variants, making accurate parts identification critical for fleet maintenance.
Below: full specifications, fluids & capacities, the factory service schedule, common service parts, verified fault codes, what owners discuss, attachment guidance, the complete assembly directory, and a serial-number reference. Complete parts lists with full OEM part numbers, exploded diagrams, quantities, and fitment data are available free in Heavy Parts AI.
Komatsu SA6D155-4A(S/N 50816-UP) specifications
Engine
| Model | SA6D155-4A |
| Gross Power | 410 hp (306 kW) |
| Power Measured At | 2000 rpm |
| Displacement | 1175.4 cu in (19.26 L) |
| Cylinders | 6 |
| Aspiration | Turbocharged |
Weights
| Operating Weight | 97,907.3 lb (44,408 kg) to 105,557.4 lb (47,878 kg) varies by configuration/series |
Dimensions
| Transport Length (w/ Blade) | 28.55 ft (8.70 m) to 30.19 ft (9.20 m) varies by configuration/series |
| Transport Length (w/o Blade) | 18.38 ft (5.60 m) to 18.57 ft (5.66 m) varies by configuration/series |
| Transport Width (Over Tracks) | 9.91 ft (3.02 m) to 9.95 ft (3.03 m) varies by configuration/series |
| Transport Height (To Top Of Cab) | 12.41 ft (3.78 m) to 13.54 ft (4.13 m) varies by configuration/series |
| Ground Clearance | 1.86 ft (0.57 m) to 1.89 ft (0.58 m) varies by configuration/series |
| Track Gauge | 7.42 ft (2.26 m) |
| Standard Shoe Size | 24.02 in (610 mm) |
| Ground Pressure | 12.52 psi (86.3 kPa) to 12.66 psi (87.3 kPa) varies by configuration/series |
Performance
| Max Speed - Forward | 7.8 mph (12.5 km/h) to 7.9 mph (12.7 km/h) varies by configuration/series |
| Max Speed - Reverse | 7.8 mph (12.5 km/h) to 7.9 mph (12.7 km/h) varies by configuration/series |
| Transmission Type | TF |
| Forward Gears | 4 |
| Reverse Gears | 4 |
Service capacities (summary)
| Fuel Tank Capacity | 198.2 gal (750 L) |
| Cooling System Fluid Capacity | 45 gal (170 L) to 47.6 gal (180 L) varies by configuration/series |
Values vary by configuration, region, and serial range — confirm against your machine before planning transport or lifts.
Komatsu SA6D155-4A(S/N 50816-UP) maintenance schedule
| Service interval | Tasks |
|---|---|
| Every 10 h |
|
| Every 250 h |
|
| Every 500 h |
|
| Every 1,000 h |
|
| Every 2,000 h |
|
Servicing the SA6D155-4A(S/N 50816-UP) beyond the schedule
Predictive Maintenance & Fluid Analysis
Utilize Komatsu KOWA fluid analysis at every 500-hour interval to monitor engine wear metals (iron, copper, lead, aluminum) and contaminants like silicon (dirt) or sodium (coolant). Track hydraulic oil particle count and viscosity to detect pump or valve wear early. Monitor coolant pH, SCA concentration, and glycol content to prevent liner cavitation and corrosion. KOMTRAX telematics should be configured to alert for DEF levels and fault codes, ensuring timely intervention before catastrophic failure occurs.
Corrective & Common Repairs
Address frequent issues in the SA6D155-4A by inspecting the air intake manifold and aftercooler for leaks, which can cause excessive smoke and power loss. Check the fuel injection pump and nozzle lines for leaks or pressure drops. Replace worn piston rings and cylinder liners if compression drops or oil consumption rises. Inspect the turbocharger shaft play and bearing condition. Verify the integrity of the exhaust manifold gaskets and turbocharger mounting bolts to prevent heat damage and exhaust leaks.
Overhaul & Rebuild Points
Plan for a major overhaul when undercarriage wear exceeds limits or engine performance drops significantly. Key rebuild components include pistons, connecting rods, cylinder liners, and valve guides. Replace the turbocharger if shaft play or bearing wear is detected. Inspect the crankshaft for journal wear and replace bearings if clearance exceeds specifications. Ensure the cylinder head is machined flat and replace all gaskets, including the head gasket and valve cover gaskets, during reassembly.
Seasonal & Environment Servicing
In high-altitude operations (up to 4,000 m), adjust the engine for reduced air density to maintain power output. Use Komatsu Super-coolant AF-NAC in extreme temperatures to prevent freezing and boiling. In dusty environments, inspect the air pre-cleaner and outer air filter element more frequently. In cold weather, ensure the fuel system is free of water and use appropriate grade fuel to prevent gelling. Check the battery charge and alternator output regularly, as cold temperatures reduce battery capacity.
SA6D155-4A(S/N 50816-UP) common service parts
| Part number | Part | Notes | |
|---|---|---|---|
| 600-311-8291 | Cartridge,Fuel Filter | Fuel system service | Check fitment → |
| 6127-71-6203 | Fuel Filter Ass'Y | Fuel system service | Check fitment → |
| 6128-81-7042 | Element Assembly, Air Cleaner | Air intake service | Check fitment → |
| 6127-21-6521 | Gasket,Oil Filter | Lubrication service | Check fitment → |
| 6631-51-5000 | Oil Filter Ass'Y | Lubrication service | Check fitment → |
Always confirm against your machine's serial number — cross-check any part in Heavy Parts AI before ordering.
SA6D155-4A(S/N 50816-UP) fault codes & troubleshooting
| Code | Meaning | Likely cause | What to do |
|---|---|---|---|
| CA115 | Engine crankshaft speed sensor failure | Broken sensor, wiring issue, or connector corrosion | Replace the speed sensor and verify voltage at the pin connector |
| CA111 | Internal engine controller fault | ECM hardware failure | Replace or reprogram the ECM |
| CA441 | Battery voltage too low | Weak battery or charging system failure | Replace the alternator or battery; check the voltage regulator |
| CA442 | Battery voltage too high | Faulty voltage regulator or alternator | Replace the alternator or battery; check the voltage regulator |
| CA234 | Engine overspeed | Throttle calibration error, engine load cycle issue, or operator misuse | Verify throttle calibration and engine load cycle |
| CA122 | Intake air pressure high voltage | Intake pressure sensor malfunction or wiring issue | Verify the intake pressure sensor and wiring |
| CA123 | Intake air pressure low voltage | Sensor short or airflow restriction | Check for a sensor short or an airflow restriction |
| CA153 | Intake air temperature sensor error (high) | Faulty IAT sensor | Replace or test the IAT sensor |
| CA154 | Intake air temperature sensor error (low) | Faulty IAT sensor | Replace or test the IAT sensor |
| CA451 | Common rail pressure sensor feedback value too high | Rail sensor malfunction or actual overpressure condition | Diagnose the fuel rail pressure sensor or pump lines |
Codes and remedies are general guidance for this model family — always confirm with diagnostic tooling and your dealer before major repairs.
SA6D155-4A(S/N 50816-UP) attachments & work tools
Bulldozer Blades
The SA6D155-4A engine (S/N 50816-Up) powers the Komatsu D355A series crawler tractors, which are equipped with approximately 155-inch (3.94 m) wide 4-way dozer blades. Factory configurations for this class typically include rear auxiliary hydraulics to operate the blade and ripper functions.
Ripper Attachments
Rear-mounted multi-shank rippers are standard for the D355A crawler tractor class. These attachments require rear auxiliary hydraulic connections and are designed for heavy-duty land clearing and soil penetration tasks consistent with the machine's 410 hp output.
Undercarriage Components
The D355A-1 configuration utilizes track shoes with a width of 28.8 inches (73.9 cm) and a track pitch of 10.25 inches (26.0 cm). The undercarriage assembly includes 7 track rollers per side and 2 carrier rollers per side, supporting an operating weight of approximately 97,907 lbs (44,407 kg).
Engine Guarding & Air Intake
The SA6D155-4A engine (S/N 50816-Up) is a turbocharged and aftercooled unit. Factory options include heavy-duty air pre-cleaners and cartridge-type air cleaners (specified for engine serial numbers 24805 and up) to protect the intake system in dusty construction environments.
All SA6D155-4A(S/N 50816-UP) assemblies by section
Every catalogued assembly group for the Komatsu SA6D155-4A(S/N 50816-UP). Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.
Cooling System
Komatsu : Sa6d155-4a(S/N 50816-Up) : Cooling System : Cooling Fan And Accessory Drive
| 01***35 | Bolt, Mounting - Flywheel Housing End | 2 |
| 01***35 | Screw | 7 |
| 01***10 | Nut,(Dust?Drip Proof? Trimming S.) | 2 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Cooling System : Corrosion Resistor And Piping
| 01***20 | Bolt,(Sandy? Dusty Terrain Spec.) | 1 |
| 01***30 | Bolt,(For France Noise Suppression) | 8 |
| 01***25 | Washer,Spring?(Sandy And Dusty Spec.) | 1 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Cooling System : Tension Pulley
| 01***20 | Bolt,(Sandy? Dusty Terrain Spec.) | 7 |
| 01***30 | Bolt,Radio Controlled Slag Handling | 3 |
| 01***20 | Bolt | 2 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Cooling System : Water Pump (1/2)
| 01***20 | Bolt,(Sandy? Dusty Terrain Spec.) | 4 |
| 01***30 | Bolt,(For France Noise Suppression) | 4 |
| 01***25 | Stud | 6 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Cooling System : Water Pump (2/2)
| 01***40 | Bolt,(For Position Fixing) | 4 |
| 01***30 | Bolt,(For France Noise Suppression) | 2 |
| 01***35 | Bolt, Mounting - Flywheel Housing End | 3 |
Cylinder Block
Komatsu : Sa6d155-4a(S/N 50816-Up) : Cylinder Block : Camshaft And Tappet
| 04***35 | Key | 1 |
| 61***30 | Plug, No. 4 | 1 |
| 61***03 | Camshaft Ass'Y | 1 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Cylinder Block : Crankshaft And Vibration Damer
| 01***25 | Bolt - Rear Guard Mounting | 6 |
| 01***36 | Washer,Radio Controlled Slag Handling | 6 |
| 04***40 | Key | 1 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Cylinder Block : Cylinder Block
| 01***18 | Bolt | 6 |
| 01***25 | Bolt,(Without Auto Priming System) | 8 |
| 01***16 | Bolt,(Sandy And Dusty Spec.) | 1 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Cylinder Block : Flywheel And Flywheel Housing
| 01***25 | Bolt,(Sandy? Dusty Terrain Spec.) | 8 |
| 01***45 | Bolt, Mount Bracket | 4 |
| 01***50 | Bolt | 1 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Cylinder Block : Gear Case And Cover
| 01***12 | Bolt,(Without R.P.C.U.) | 2 |
| 01***40 | Bolt,(Not Used With Cab) | 2 |
| 01***55 | Screw | 4 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Cylinder Block : Oil Pan
| 01***20 | Bolt,(Sandy? Dusty Terrain Spec.) | 1 |
| 01***25 | Bolt,(Without Auto Priming System) | 2 |
| 01***25 | Bolt,(Sandy? Dusty Terrain Spec.) | 2 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Cylinder Block : Piston And Connecting Rod
| 61***20 | Ring,Snap | 2 |
| 61***10 | Pin,Piston | 1 |
| 61***42 | Crank Pin Metal A | 6 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Cylinder Block : Power Take Off
| 01***20 | Bolt,(Large Capacity Type) (Std) | 6 |
| 01***30 | Bolt,(For France Noise Suppression) | 6 |
| 01***30 | Bolt,Radio Controlled Slag Handling | 6 |
Cylinder Head
Komatsu : Sa6d155-4a(S/N 50816-Up) : Cylinder Head : Air Cleaner And Pre-Cleaner
| 01***30 | Bolt | 4 |
| 07***09 | Clamp, Hose | 2 |
| 09***61 | Plate? Instruction,(Japanese-English) (Not Shown) | 1 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Cylinder Head : Air Intake Manifold And After Cooler
| 01***25 | Bolt,(Without Auto Priming System) | 4 |
| 01***35 | Bolt,(Without Auto Priming System) | 2 |
| 01***40 | Bolt,(For Position Fixing) | 2 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Cylinder Head : Compression Release
| 01***35 | Bolt,(Without Auto Priming System) | 1 |
| 01***25 | Washer,Spring?(Sandy And Dusty Spec.) | 1 |
| 04***20 | Key | 1 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Cylinder Head : Cylinder Head
| 01***30 | Bolt,(For France Noise Suppression) | 6 |
| 01***30 | Washer,Spring(Sandy?Dusty Terrain S.) | 6 |
| 07***16 | Plug, Expansion | 2 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Cylinder Head : Exhaust Manifold And Turbocharger
| 01***10 | Bolt | 12 |
| 01***25 | Capscrew | 6 |
| 07***08 | Plug,(Without Auto Priming System) | 2 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Cylinder Head : Muffler
| 01***95 | Screw | 1 |
| 01***30 | Bolt | 2 |
| 01***65 | Screw | 1 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Cylinder Head : Rocker Arm And Housing
| 01***05 | Bolt (Kit) | 21 |
| 01***10 | Bolt, Mount Filler Tube | 3 |
| 01***25 | Washer,Spring?(Sandy And Dusty Spec.) | 1 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Cylinder Head : Rocker Arm Housing Cover
| 01***22 | Bolt,(Cold Terrain Spec.) | 3 |
| 01***40 | Bolt,(For Position Fixing) | 2 |
| 01***25 | Bolt,(Sandy? Dusty Terrain Spec.) | 2 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Cylinder Head : Turbocharger
| 01***30 | Bolt | 4 |
| 04***50 | Screw | 2 |
| 07***95 | O-Ring (Kit) | 2 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Cylinder Head : Water Manifold And Thermostat
| 01***40 | Bolt,(For Position Fixing) | 4 |
| 01***30 | Bolt,(For France Noise Suppression) | 3 |
| 01***35 | Bolt, Mounting - Flywheel Housing End | 9 |
Electrical System
Komatsu : Sa6d155-4a(S/N 50816-Up) : Electrical System : Alternator (35a)
| 60***40 | Alternator A. (35a) | 1 |
| DK***12 | Washer | 1 |
| DK***02 | Washer,Spring | 1 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Electrical System : Alternator (50a)
Komatsu : Sa6d155-4a(S/N 50816-Up) : Electrical System : Alternator And Mounting
| 01***25 | Bolt,(Without Auto Priming System) | 4 |
| 01***40 | Bolt,(Dust And Dirt Protection) | 2 |
| 01***25 | Bolt - Rear Guard Mounting | 1 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Electrical System : Alternator Drive
| 01***16 | Bolt (Welded) | 6 |
| 01***40 | Bolt,(Dust And Dirt Protection) | 3 |
| 01***10 | Nut,Lock | 1 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Electrical System : Safety Relay
| 60***60 | Safety Relay A.,(For 800w? 1200w Alternator) | 1 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Electrical System : Starting Motor (11kw)(#.-)
| 60***12 | Starting Motor Ass'Y,(11kw) | 1 |
| SD***X0 | Pinion Clutch Ass'Y | 1 |
| SD***X9 | Switch Ass'Y,Engage | 1 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Electrical System : Starting Motor (11kw)(#50816-.)
| 60***11 | Starting Motor Ass'Y,(11kw) | 1 |
| SD***09 | Metal | 1 |
| SD***20 | O-Ring | 2 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Electrical System : Starting Motor And Mounting
| 01***45 | Bolt,(For Slag Handling) | 3 |
| 01***48 | Washer,Spring? Single Flange | 3 |
| 07***35 | O-Ring,Cage? Transfer Gear | 1 |
Fuel System
Komatsu : Sa6d155-4a(S/N 50816-Up) : Fuel System : Auto Priming System (1/2)
| 01***12 | Bolt,(Without R.P.C.U.) | 4 |
| 01***60 | Bolt,(Without Alternator Bracket) | 8 |
| 01***20 | Bolt,(Large Capacity Type) (Std) | 2 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Fuel System : Auto Priming System (2/2)
| 01***25 | Bolt,(Without Auto Priming System) | 1 |
| 01***06 | Nut, Regular Hexagon (M8-1.25) | 1 |
| 01***25 | Washer,Spring?(Sandy And Dusty Spec.) | 1 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Fuel System : Auto Priming System Control Unit
| 01***08 | Screw, Terminal | 7 |
| 01***12 | Screw,(Additional Sun Visor) | 2 |
| 01***12 | Screw,(With Articulate Indicator) | 8 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Fuel System : Automatic Timer
| 61***32 | Automatic Timer A | 1 |
| DK***00 | Washer | 1 |
| DK***00 | Flyweight | 2 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Fuel System : Fuel Filter And Piping
| 01***12 | Bolt (M8-1.25x12) | 1 |
| 01***20 | Bolt,(Large Capacity Type) (Std) | 1 |
| 01***30 | Bolt,(For France Noise Suppression) | 3 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Fuel System : Fuel Injection Pump (Feed Pump)
| DK***00 | Valve,Check | 4 |
| DK***20 | Bolt,Joint | 1 |
| DK***30 | Eye,Joint | 1 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Fuel System : Fuel Injection Pump (Governor) (1/2)
| DK***00 | Gear | 1 |
| DK***00 | Connector | 1 |
| DK***00 | Shim? 2.00mm,(High Altitude Spec.) | 0 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Fuel System : Fuel Injection Pump (Governor) (2/2)
| DK***80 | Shim? 0.5mm | 0 |
| DK***00 | Bushing | 1 |
| DK***40 | Gasket,Air Compressor | 4 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Fuel System : Fuel Injection Pump (Pump) (1/2)
| 61***20 | Injection Pump Ass'Y | 1 |
| 61***21 | Injection Pump Ass'Y | 1 |
| 61***22 | Injection Pump Ass'Y | 1 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Fuel System : Fuel Injection Pump (Pump) (2/2)
| DK***20 | Plunger Block A | 6 |
| DK***00 | Shim? 0.875mm | 0 |
| DK***00 | Shim? 0.500mm | 0 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Fuel System : Fuel Injection Pump And Piping (1/2)
| 01***12 | Bolt (M8-1.25x12) | 1 |
| 01***16 | Bolt,(For Slag Handling) | 1 |
| 01***30 | Bolt,(Cold Terrain Spec.) | 8 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Fuel System : Fuel Injection Pump And Piping (2/2)
| 01***10 | Bolt | 1 |
| 01***16 | Bolt,(For Slag Handling) | 2 |
| 01***45 | Bolt,(S6d155-4b) | 1 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Fuel System : Fuel Injection Pump Drive And Service Meter
| 01***30 | Bolt,Radio Controlled Slag Handling | 6 |
| 01***35 | Bolt - Torque Converter Totransmission Mounting | 1 |
| 01***30 | Bolt, Bolt | 6 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Fuel System : Fuel Nozzle And Spill Pipe
| 07***12 | Gasket,Mechanical Pump Piping | 14 |
| 61***12 | Pipe,Fuel Supply | 6 |
| 61***33 | Nozzle,Fuel | 1 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Fuel System : Water Separator
| 07***12 | Gasket,Mechanical Pump Piping | 1 |
| 60***31 | Separator Assembly, Water | 1 |
| 60***60 | Plug,Drain (4d105-5h? 4d105-5t) | 1 |
Lubricating Oil System
Komatsu : Sa6d155-4a(S/N 50816-Up) : Lubricating Oil System : Bypass Filter
| 01***75 | Bolt,(For 75a Alternator) | 2 |
| 01***15 | Bolt | 2 |
| 01***36 | Washer,Radio Controlled Slag Handling | 4 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Lubricating Oil System : Camshaft Lubricating Oil Piping
| 07***10 | Connector,Pipe | 6 |
| 61***40 | Nozzle,Oil | 12 |
| 61***12 | Pipe,Oil | 2 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Lubricating Oil System : Lubricating Oil Cooler
| 01***20 | Bolt,(Large Capacity Type) (Std) | 2 |
| 01***30 | Bolt,(For France Noise Suppression) | 2 |
| 01***35 | Bolt, Mounting - Flywheel Housing End | 19 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Lubricating Oil System : Lubricating Oil Filter
| 01***70 | Bolt, Spacer | 2 |
| 01***40 | Bolt,(Dust And Dirt Protection) | 8 |
| 01***80 | Bolt,(Shim 5 Pieces Over) | 2 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Lubricating Oil System : Lubricating Oil Pump
| 01***20 | Bolt,(Large Capacity Type) (Std) | 2 |
| 01***25 | Bolt,(Sandy? Dusty Terrain Spec.) | 2 |
| 01***50 | Bolt - Torque Converter Totransmission Mounting | 2 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Lubricating Oil System : Oil Strainer And Piping
| 01***14 | Bolt | 2 |
| 01***22 | Bolt | 3 |
| 01***25 | Bolt,(Sandy? Dusty Terrain Spec.) | 5 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Lubricating Oil System : P.T.O. Lubricating Oil Piping
| 01***22 | Bolt | 2 |
| 01***30 | Bolt,(For France Noise Suppression) | 2 |
| 01***30 | Washer,Spring(Sandy?Dusty Terrain S.) | 4 |
Komatsu : Sa6d155-4a(S/N 50816-Up) : Lubricating Oil System : Turbocharger Lubricating Oil Piping
| 01***10 | Bolt | 1 |
| 01***35 | Bolt,(Without Auto Priming System) | 2 |
| 01***35 | Bolt, Mounting - Flywheel Housing End | 2 |
Tool And Kit
Komatsu : Sa6d155-4a(S/N 50816-Up) : Tool And Kit : Gasket Kit
| 01***12 | Washer,Lock (K2) | 3 |
| 01***12 | Washer,Lock (K2) | 4 |
| 01***08 | Washer,Lock (Kit) | 1 |
SA6D155-4A(S/N 50816-UP) serial number reference
The engine serial plate is mounted on the left side of the engine block, typically near the injection pump. The prefix is the alphanumeric code at the start of the engine model designation (e.g., SA6D155-4A), followed by the serial number which indicates the production sequence.
| Prefix | Identifies | Notes |
|---|---|---|
| SA6D155-4A | Standard | Serial range 50816-UP. Factory parts catalog and engine guide listings identify this as the primary configuration for the specified serial block. |
| SA6D155-4A-35 | Emissions Variant | Serial range 20338-UP. Listed in the same engine guide template as a distinct variant requiring specific parts (e.g., pre-heater nozzles). |
Frequently asked questions
What engine does the Komatsu D355A-1 use?
The Komatsu D355A-1 Crawler Tractor uses the Komatsu SA6D155-4A, a turbocharged, six-cylinder diesel engine rated at 410 hp.
What is the operating weight of the Komatsu D355A-1?
The operating weight of the Komatsu D355A-1 varies by configuration, ranging from 97,907 lb to 105,557 lb (44,400 kg to 47,900 kg).
What engine replaced the SA6D155-4A?
The SA6D155-4A was replaced by the SA6D155-4A-35 (S/N 20338-UP) to meet stricter emissions standards.
What SA6D155-4A(S/N 50816-UP) owners discuss
What are the typical powertrain and hydraulic behaviors associated with the Komatsu SA6D155-4A engine series?
What undercarriage or wear patterns are typical for machines powered by this engine?
What are the known engine quirks for the SA6D155-4A series?
What are the common electrical and sensor issues for this engine and machine type?
What should be checked when buying a used SA6D155-4A(S/N 50816-UP) engine or machine?
How does the SA6D155-4A engine handle high-altitude or extreme temperature operations?
Compiled from owner and technician discussions across the industry — experiences vary by serial range and machine history.
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